A vast range of primary and auxiliary locking systems are available for secure enclosures ranging from simple box locks to highly complex multipoint locking systems as applied to high security safes.
The type of locking system required for any given situation is governed by the level of security, the nature of the enclosure concerned and the manner in which the access point of the enclosure operates. Generally the access point of a given enclosure will operate by way of a hinged and pivoting action or by way of a sliding action.
The locking systems applicable to these two different modes of access point operation clearly require different locking mechanisms and both systems provide strengths and weaknesses of design.
A particular weakness of the hinged access point system involves the vulnerability of the hinged region which can be exposed to tampering and/or vandalism and when such access points or doors are secured only by a sliding bolt system on the free end, the removal of the hinging mechanism will allow such doors to be moved by a simple sliding action to withdraw the whole door and sliding bolt from the enclosure and the enclosure's keeper. In order to address such problems, pivoted doors can be provided with combination sliding and drop bolting systems and/or provided with projecting tabs at the hinged edge of the door which can be adapted for insertion into indentations at or near the hinged edge of the enclosure. Whilst such features assist in improving security of such enclosures, such locking systems are still vulnerable to vandalism where both the hinge region and the tab region can be exposed to attack thereby again leaving the door able to be removed by a sliding action simply withdrawing the slide bolt from the enclosure's keeper.
Such a situation applies to the design and construction of automatic teller machines (ATMs) which provide an enclosure in the form of a steel cuboid box having a rear hinged door as the primary access point. Such automatic teller machines rely on two robust hinges applied to the top and bottom of the door and projecting tabs along the pivot edge of the door which insert into indentations formed in the edge of the enclosure. The sliding bolt of the automatic teller machine operates from the other side of the door and engages the keeper formed in the enclosure.
To date, such automatic teller machines remain vulnerable and can be attacked with a blow torch to remove the top and bottom hinges and the tabbing system.
Such an attack leaves these doors vulnerable and an auxiliary locking system to enhance the current sliding bolt system to prevent the opening of such doors either by rotation around the hinges or by sliding action would be desirable.